Amino aldehydes, asymmetric hydroformylation

SCHEME 14.4. Asymmetric hydroformylation of aUcenes can provide versatile aldehydes which may be used for the Strecker syntheses of a-amino acids. 

Zhang and co-workers used asymmetric hydroformylation of A/-allylamides to generate chiral p -amino aldehydes. These are useful building blocks for the synthesis of natural products with the Boc-protected amino aldehyde 6 being a key intermediate in the synthesis of cyclamenol A (Scheme 14.14). This is an unusual noncarbohydrate, nonpeptide inhibitor of leukocyte adhesion to endothelial cells and is viewed as a possible source of an anti-inflammatory agent for treatment of the symptoms related to asthma, arthritis and strokes and others. 

SCHEME 14.14. Asymmetric hydroformylation allows access to chiral amino aldehydes, which can be applied in the synthesis of natural products. 

Zhang XW, Coo BN, Yu SC, Zhang XM. Rhodium-catalyzed asymmetric hydroformylation of A-allylamides highly enantioselective approach to beta(2)-amino aldehydes. Angew. Chem. Int. Ed. 2010 49 4047 050. 

Hydroformylation of various heterofunctionalized olefins can be carried out with a number of chirally modified catalysts. Asymmetric induction is usually higher than with unfunctionalized hydrocarbons, presumably, due to additional binding of the substrate to the catalysts65,75. Thus, this method is applicable to the synthesis of hydroxy and amino carboxylic acids and other conversion products of primary functionalized aldehydes. These results are compiled in Table 7. 

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